#help-38
1 messages · Page 105 of 1
are you sure its not?
no it is, I forgot I didn't give you the whole question
Because, what they basically had to do was
make the bottom 2x^2
Such that theota on denominator and numerator is same
Which become 1 basically
no I get that
no I'm confused on why the equated number so it balances out is 2*x^2/x^2
I would assume it would just be like x^2/x^2
why is there the 2 on top?
shouldn't they be the same?
AH
like if you want to add 1 to like 3x you need to also put a minus 1
mhm
To get two in the bottom
They should have multiplied with
2/2
Now why they did the stuff on the RHS, no idea
But basically all u had to do was this
2/2
yes
wouldn't that cause the 2 to be on the top also
yes
since u cant just introduce in a new number
in the denominator
u gotta multiply the top with the same number
so it essentially cancels out
I need to know how this works out I am so lost 
it doesn't make sense to me
The equation on the right says
When x approaches 0, sin(x)/x becomes 1
If you take sin(0.0001)/0.0001, the answer would be 1
I get the theorem
I don't get the equating bit
I GET THE THEOREM
You cant change anything in the bracket, but u can change the denominator
OH GOD
THEN WAHT DO U NOT GET
IM EXPLAINING U TO STEPS TO GETTING THE ANSWER
IN THE QUESTION ??!?!?!?!?
I just don't get how the 2 on the bottom equates to 2*x^2/x^2
huh
becuse if you want 3x with a 1
it'll be 3x +1 -1
because we can't just add random number all willy nilly
mate
don't look at the working
solve it yourself
that's what i suggest
I got no idea what yo working has been done but
Do it on your own, solve it, get yo answer and ull be all merry and happy
Cant help u with deciphering that maths
so you can't tell me why adding a 2 on the bottom needs an equivalent of 2*x^2/x^2
it doesn't need an equivalent of 2x^2/x^2
it just needs 2
Because 2x^2/x^2 is literally 2
so why wasn't it just 2, why did they have to add the x^2 to it
huh
they might've just thought just replacing the x² with 2x² is easier to see
since you added the 2x² on the bottom, you must multiply it by 2x² on the top
and the x² before stays
thus 2x²/x²
so if I were to multiply them together I would get the original right?
but yeah this guy was trying to tell you that 2x² / x² is 2
and you put that 2 below the original
which all boils down to divide and multiplying 2
rough life man
made me wanna kms
I guess it never occured to me that the equivalent of adding stuff to the demoniator is multiplication :V
division*
adding stuff to the numerator is multiplication
I mean't it in the equating context but yea thats right
alright thanks for the help
soz :V
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,tex -sin^{7}(\frac{1}{x})+sin^{7}(\frac{1}{e})
suds
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i did this
i dont know what im doing wrong
, tex bc i used the definite intergral thing of $ \int_{b}^{a}=f(a)-f(b)
suds
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and i know using the ftoc its basically unchanged but i dont understand why you can't use the definite integral formula with it, because its the same as integrating the thing and differentiating it which would be -sin^7(1/x) + sin^7(1/e)
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For what values of $n$ does $(x+\frac{1}{x})^n$ have a term independent of $x$ when expanded?
BOHO
i applied general term to this and i got n = 2k. does that mean any non-negative even integer of n will have a term independent of x? (as long as k is a non-negative integer)
prob
also
Find the values of $n$ such that the expansion of $(3x^2+\frac{4}{x})^n$ has a non-zero $x^2$ term.
BOHO
im not sure how to do this
after i get a value of n in terms of k
i got n = 3k - 2 and subbed that in to the general coefficient thingy
and i got
$\binom{3k-2}{k} * 3^k * 4^{2k-2}\neq 0$
BOHO
idek if what im doing is right
@short cave Has your question been resolved?
@short cave Has your question been resolved?
@short cave Has your question been resolved?
In the general term, the power of x will be 2(n-r) - r = 2n - 3r.
You want this to be 0, so r = 2n/3.
For what values of n will this be an integer?
ah, I messed up the general term part anyways.
So would n just be any multiple of 3 for that to be an integer?
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How do i solve the question that is crossed out? (b)
Please don't occupy multiple help channels.
The translation is, "Point P belongs to the end leg of angle alpha, and point Q - to the end leg of angle beta. Calculate sin alpha-sin beta"
Where the coordinates of point P is (-9,3) and point Q, (2,6)
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Can someone solve this ?
why close the other channel
Someone else was typing for a long time
Nah it's ok.
because its effectively a dead channel now and time gets wasted
anyway
look up adventitous triangle
that also looks snapshotted from MindYourDecisions,
He did it by constructing a isosceles triangle. Isn't there any other way ?
trig bash probably
Can you do it ?
trig bash? no
Ok let's wait ig
not interseted in doing that
For someone else
Ok
@torn sun Has your question been resolved?
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does anyone know how to interpret this one
never seen anything like it before, it says the answer is 3/2 but idk how it got there
it's just the derivative at x=1, to solve it properly first find f(x) at that point, then substitute the values, and evaluate the limit
F(1) = 1
Idk how to solve the derivative properly at this point @wild imp
How would you go about it
did you find f(x)?
f(1) = 1
At x = 1 right?
Slope is 1 and y intercept is 1
So x + 1
Am I right?
no
try again, the slope is rise/run
the line goes from y=-1 to 2 for x=0 to 2
also the y-intercept is -1
Rise is 1 and run is 1
see its 3 and 2
so can you find f(x) now?
yes, thats right
Question
now you just need to evaluate the limit
y-axis*
@gusty mulch Has your question been resolved?
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x and y have to cross the line with a dot, but if i choose random ones like -4 and -7 it doesnt cross
u can choose a random x value
and then you have to plug that x value into:
y = -3x - 2 to get the y value
u don't randomly choose an x and y value
u can only choose one value (x or y) randomly
@rugged crag Has your question been resolved?
how do i get rid of this
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Hello, can someone confirm if width is adjustable in a frequency table
<@&286206848099549185>
- Dont ping helpers until 15 min has passed
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Could you provide some context?
@plush sequoia Has your question been resolved?
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can someone explain to me how this changed to that ?
they divided by e^b on both sides
or equivalently, they multiplied by e^(-b) on both sides
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distribute
oh
or FOIL
What do you need to subtract from that to get a^2 + b^2?
@lament stone Has your question been resolved?
ohh
-2ab
wait so i write (-2ab) right
cuz theres a minus already
just 2ab, the - takes account of that
okk
Cause (a + b)^2 - 2ab = a^2 + b^2 is what they want from you, the 2ab being what to fill in 
tysm
could u help me iwth 7?
the question below the one u jsut helped me solve
i get that its basically the same thing but (a+b)^2 has two positive signs and (a-b)^2 only has one
so what do i add to make them equal
Well, expand them both, and see what you need to add to (a - b)^2 to get (a + b)^2
i need -2ab to be +2ab
but idk how to do tht
So, -2ab + [what] is equal to +2ab?
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im asked to find the probability that there is at most two defective lamps in a random sample of 30 lamps, given that there is at least 1 defective. The probability that a lamp is defective is 0.05.
So i should just do binomial cd on my calculator where x = 1 and numtrials = 29 right? then i subtract this from 1
Not really
why?
Do you recall how to calculate probability given a certain event?
Bayes is only useful if you already have P(B given A)
Pretty sure yes
Event A = There are at most 2 deffective lamps
Event B = There is at least 1 deffective lamp
$$P(X \le 2|X \ge 1)$$
is basically
$$P(1 \le X \le 2)$$
Akuma
You're on the right track here
then i divide by the prob of event B
For P(X>=1) you just find the complement
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Characteristic 3 
a^3 = 0 
1 + a
can you find a way to use those two above facts, and find some expression involving 1 + a?
(also notice the ring is commutative!)
@stoic flame Has your question been resolved?
Thoughts on this?
(1+a)^3 = a^3 + 3a^2 + 3a + 1 = 1
Not sure when we use commutativity
Exactly that! Commutativity is what allows you to do that expansion
How come that lets us expand it?
Namely that for any commutative ring you can e.g. binomially expand
(actually just noticed this, cause it's 1
)
Was thinking of a different problem where it was similar but you needed the commutativity, showing the sum of nilpotent elements is nilpotent 
[in general though, that allows you in thinking of (a + b)^k to swap the order of multiplication in the products you end up finding, which was the thing I was thinking of haha]
I mean you dont even need char 3, do you? just do geometric series on 1+a^3
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!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
what have u done so far?
ok
then think about it this way
the fox is ahead 72 jumps
so when the dog starts it will be at 0 jumps
distance wise (as you said) the fox is ahead 3x72 = 216 distance ahead
every jump the dog gains 8 distance
whereas as the fox gains 3 distance to its already 216 distance
so can you create an algebraic relationship
for each jump j what dist_d and dist_f equals ?
thats a number
im looking for this
no total distance
dist_f = 3j + 216
dist_d = 8j
how far they have travelled
they as in each of them
i gtg now sry
@wraith hinge Has your question been resolved?
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I am just confused on what the question is asking, and how would I go about figuring said question out
Is it just asking me to put the values provided into the answer boxes?
Like, A-B would be 125 < 20?
Is it that simple? or am I overcomplicating it
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so I believe the GCD's imply that a,b and c are all coprime and thus only share the divisor of 1
Is tau the lcm
the tau function is the amount of divisors for some n
ex: tau(12) = 6 as 12 has the divisors 1, 2, 3, 4, 6, 12
Right right
therefore I think tau(abc) should simply be tau(a) + tau(b) + tau(c) - 2 (excluding that they all share a divisor of 1)?
Then it's not the sum, but the count
I believe that’s correct yes
They are all coprime
oopsie yeah that would be sigma haha
is there a more rigorous way to prove this?
Me too
Prime expansion
.
gotcha
Actually that seems incorrect
You create new divisors
For example if you take 2 and 3
Oh right, forgot about the number ab
Yeah so you need to account for the divisors being multiplied
So you need to add 2^n - n
Oh right, the divisors create new factors too
In that case this extends to the ternary case
youre essentially proving the identity extends to more pairwise coprime numbers
So it would be T(a)T(b)T(c)
so t(abc) = t(a)*t(b)*t(c)
yes
hmm, that is shockingly similiar to this then huh
as long as a,b,c are pairwise coprime
suggestion: try proving gcd(a,bc)=1
then proceex
and then say tau(a), tau(b), tau(c) have no common factors
and thus tau(a) * tau(b) * tau(c) = tau(a * b * c)?
gcd(tau(a),tau(b)) can be greater than 1 despite gcd(a,b)=1
take 3 and 5 for example
There are many similar things in math. Essentially moving from a pairwise statement to an arbitrary number of values.
wait did I mess up the proof then?
sorry just trying to understand
i would say follow my suggestion
You mean that any Pi is distinct from any Qi
ah yeah that's probably better wording
what I meant is like no (ki + 1) term will be shared
I think I have it
but why is this mission critical?
i guess now it's basicallly equiavelent to this proof but why make the distinction?
@jolly kayak Has your question been resolved?
You're trying to apply the pairwise proof to 3 (or more) terms. Before that can be done, you must first establish, as GBF said, that a and bc satisfy the condition of gcd(a, bc) = 1.
I.e. That the pairwise property holds "associatively"
ah makes sense
can I post the full proof I have here in ~ 10 minutes to check for accuracy
I can do a scanned copy as well if that's easier
question 3 for reference
@jolly kayak Has your question been resolved?
@jolly kayak Has your question been resolved?
Looks good 🙂
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confused on how to find the inverse
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.reopen
how to prove a limit does not exist using epsilon delta?
What's the exercise
like $\lim_{x\to 0} \frac1x$ for example
babario
Yeah maybe with the definition and the continuity of this function
How with the definition tho?
Proving something exists is pretty obvious, i just dont understand how to properly prove something does not exist?
Ok so I think in this type of problem WE Can go for the absurd thus WE Can use our definition
Like suppose the limit exist
So what do we know with the definition
And with the unicity of the limit you go to a contradiction
I think it will go something like that
So suppose $0 < |x| < \delta \implies \left|\frac1x - L\right| < \varepsilon$?
babario
What is delta and epsilon and L
$L\in \Bbb{R}$?
babario
But since its a contradiction we should show that for all L there exists epsilon that for all delta exists x where this doesnt hold true right?
L IS your limit right
Yea
Ok maybe I will do something like it exists a sequence in R*+ such that it converges to 0+ take 1/n and f(1/n) converges to plus infinity with f(x) =1/x
Thus the limit in 0+ is plus infinity
Make thé same with another sequence in 0- like -1/n and u will have that the limit IS -infinity so with this 2 limits no equal it doesn't have a limit on 0
@wispy raptor Has your question been resolved?
Yea that works but im curious for specifically using epsilon delta to proof
Ok I will try to do it so let me some time
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express (-1+i)^5 in polar form
Hi
can you write -1+i in polar form
you can first convert (-1 + i) into polar form
yo dude
Woah what you did.
de moivre theorem
i did
this is polar form
???
i havent studied that one yet
why
You said you want jn polar form
^
i only kno the above one
dk what the 2nd one even means
Yeah just thin 4√2 is outside
,, \sqrt 2 (\cos (135\ang) + \sin(135\ang))
inf1425
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right
exactly
.
you didnt put the iota
now u raise it to the power n by using de moivre's formula
do i have to rite the angle = 5(315) = 1575
or can i just rite 315
cuz both give equal values
its 135
no when i raise the power
for polar form you always express it as 135
and angles that are below the x axis are negative
not > 180
and after i use the de moivre theorem
what angkle am i gonna rite
315 or 1575
tan inverse of -1 is 315
its -1 + i not 1 - i
i didnt rite -45
same thing
?
can u plot (-1 + i) on the complex plane and see what angle you get from the x axis if drawing a line from the origin to (-1 + i)
ummm
would it be 315
yeah
180-45 = 135
modulo 360 u get 315 but you dont write 315
the hole time
u write -45
instead of 1575
for polar form u never write angles above 180
ok
its just a rule
if the angle is below the x axis it becomes negative and is taken clockwise
rather than anticlockwise
your final answer should be 4 sqrt(2) * (cos(-45) + isin(-45))
can i put the -45 out of the sine
as in
oh
you can but it won't have any use
polar form is normally written as r.e^(itheta)
,, 4\sqrt 2 e^{i \cdot -45^\circ}
inf1425
is what you would normally write
tf is this
inf1425
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did I solve this correctly?
first i used cross product of v1 x v2
then to make 0 vector, i used back substitution for a, b, c
to make each entry in the vector = 0
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How do i do #36?
uoǝu
@daring dragon Has your question been resolved?
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Hi, I don't rly understand what is happening in the second equal sign?
(for context this is aproximation of differential equations using series)
It's a simple multiplication really
Multiply the content of the brackets with the sum one by one
x multiplied by the sum gives the same sum, only that each member is now k+1 degree
Since x^k * x = x^k+1
and then the other member is 1 so it's just the sum again
oh jezus christ
I was looking for some complicated series expansions
thanks hahaha
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Can someone help me on number 8 I think its letter B but im not sure
,rccw
Umm because its intersecting in -2
How does it work, I didn't really pay attention to that in class
do you understand the terms slope/gradient and y-intercept
No
No lol
the slope is how much y changes by when x increases by 1, the y intercept is where the line crosses the y axis, ie when x=0
straight lines have the form y=mx+c where c is the y intercept and m is the slope
you said m was -2, but that would mean the line was going down as x increases, not up
and you were claiming the y intercept was -4, which is also not true
Oh ok then is it a?
si
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Explain why R[x], the ring of real polynomials in the variable x, has no
invertible elements which are not constant.
can i please get help on how to answer this, pls? (above, 6 and below, 4)
and also parts (i), (ii) and (iv) of this
for 4(ii), i've said it's not isomorphic because there doesn't exist any a,b in 2Z which will add up to give any of the odd numbers in Z
is that right??
@visual hollow Has your question been resolved?
Not constant = degree at least 1
Multiplying a polynomial by some other nonzero polynomial never makes its degree smaller (true for constant polynomials, true for monomials, true for all nonzero polynomials by induction)
Therefore, for any non-constant polynomial, i.e. one with degree at least 1, there can exist no polynomial such that their product would be 1 (which has degree 0)
uh
(true for constant polynomials, true for monomials, true for all nonzero polynomials by induction)
is there supposed to be an "except" before this?
x^3 has degree 3
If you multiply it by any nonzero polynomial, it will have degree at least 3
I guess probably the best way to see that is to consider the cofficient of the highest degree term of the polynomial
so if you multiply it by 5x^10 + 2x^3 for example
Then the resulting polynomial will have a nonzero term of degree 13, which is at least 3
And I guess more generally if you have any arbitrary polynomial like 10x^3 + 2x^2 + 3 then if you multiply that by any polynomial of degree k where the highest degree term has the nonzero coefficient a, then the product polynomial will have a term of degree k + 3 with the coefficient 10a, which in particular is nonzero
and all of this means that you can't invert the expression because the constant polynomial P(x) = 1 has degree 0
You might want to remind yourself of how polynomials are multiplied together
why??
Multiplying a polynomial by some other nonzero polynomial never makes its degree smaller
i understand and agree with this
if you agree with that then that's pretty much all you need
just not the bracketed part
well I actually take back the part in parenthesis
I think this is a better way to see it
but the problem statement didn't really seem to ask for a proof anyway
so if you're convinced by "multiplying a polynomial by a nonzero polynomial never makes its degree smaller" then you can just roll with that
a monomial is a polynomial that only consists of one nonzero term
So 1, x, x^2, 3x^3, are all examples of monomials
what's a summand
a fancy term for a thing that's being summed
the things you're summing with
ye
ok
(but that's me speaking very loosely because I would certainly count 3x+5x as a monomial because it simplifies to 8x)
Therefore, for any non-constant polynomial, i.e. one with degree at least 1, there can exist no polynomial such that their product would be 1 (which has degree 0)
i don't get this - there can exist no polynomial such that their product would be 1 (which has degree 0)
yh i would too
So you're given a polynomial of degree at least 1 (a non-constant polynomial)
If you can find some other (nonzero) polynomial such that their product is 1 then you call that polynomial an invertible element
If no such polynomial exists, then the polynomial is not invertible
And my claim is that a polynomial like 5x^2 will have no other polynomial such that their product is 1
because if such a polynomial existed then multiplying 5x^2 by that polynomial would make the degree smaller
which we know is impossible
"their product"???? the non-constant degree 1 polynomial * what??
You're given 5x^2
If there exists some nonzero P such that 5x^2 * P = 1 then you call 5x^2 an invertible element of the ring
No such P, however, can exist, because if it did, then you'd use multiplication to lower the degree of 5x^2, which is impossible
ah ok
i get it
why 1 btw?
why do they have to multiply to 1
is it coz that's the multiplicative identity?
so if you multiply it by
5x^10 + 2x^3for example
Then the resulting polynomial will have a nonzero term of degree 13, which is at least 3
x^3 * (5x^10 + 2x^3), is this what you mean?
Yes exactly
yup
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I have a model with three variables a_1, a_2 and w and I would like to know how I can find the optimal values of these three to minimize the error defined by the picture.
How would I go about doing that?
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Where should i start with
have you tried partial fractions?
^
I didnt learn that
what did u learn
Is there any other way or show me how to do it
Here is what i did for the last problem
this looks like a weird way to do partial
from how i normally do it at least
but that looks like partials
Can u show me how u do it
take x^2 common from the denominator and let 1/x=t
partial fractions is just a methodological way of doing what you've done in the previous problem, except breaking 8 in terms of x^2 and x-2 is not easy mentally, so we form a system of equations by letting the fraction equal to A/x + B/x^2 + C/x-2.
I get
tho i try to avoid that as much as possible since forming that system of eqns can take a lot of time
$\int{\frac{2-4t}{1+2t}}dt$
San
Wait ill go home first now at school
unless you put -1/x=t instead
which is also fine as long as you substitute it back correctly
I should get 2t+2ln|2t-1| right
where t=1/x yes
perfect
Man tysm t=1/x was a life saver man
My teacher did partial fraction i cannot understand shi so many stuff going on
its fine, tho i recommend you to learn partial fractions as well, theyre handy(sometimes)
actually what you've done here is partial fractions only, but without making the 'formal' equations
we ve basically broken down this thing into partial fractions
this one is mentally doable
but the other one with the cubic in the bottom was a little complex for breaking it mentally, so we need to form some equations
Idk what was it i did it like my extra class teacher
It sure is i cant understand it and i tried partial also but it was so complicated
Yeah it would have been calculative
doing stuff like that is my last resort
when i cant think of anything
do you want me to guide you through that method as well or are you good?
Nah im good ill watch some youtube later maybe
Tysm I couldn’t even think of t=1/x
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What type of equation is this?
i cant help but you may want to translate that for someone who can help
That line means consider the equation
They call it the equation
but I have never seen it before
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Can someone look over this? So would something like.
If W= {v1,v2,v3,vn } is the set of vectors in the third quadrant vector space V, then W will be the basis if:
W spans W
W is linearly independent
Make sense for number seven
Yep, linearly independent spanning set would do as the definition
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I’m stuck on this question
10b, I have worked out 10a
I’m not sure how to workout the the constant and where to start.
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<@&286206848099549185>
so we know that : (a-b)^5 = a^5 - 5a^4b + 10a^3b^2 - 10a^2b^3 + 5ab^4 - b^5
substituting for 1 and 4x we get :
X is 0.25?
(1-4x)^5 = 1 - 5(4x) + 10(4x)^2 - 10(4x)^3 + 5(4x)^4 - (4x)^5
Is that part b?
isn;t it ?
I find this confusing to understand
yes it's b
well I can explain it to you in two ways
on is the analytic and other one the quick one
which one would you like
Which one would I use more of in tests?
I don't know tbh
Could you explain the one that is easier to understand and to do? Just in your opinion
do you understand that?
Yes, so in this case a would be 1 and b would be 4?
no b would be 4x
No sorry that’s what I meant
oh ok
yes it is like that
but just for simplicity instead of multiplying by one I just skipped that
And how do I compare the coefficient
you also need to multiply it with the (1+ax+bx^2) part
But it says first 3 terms of the expansion of (1-4x)^5
well that works too
because you only need these to get your result because for any higher powers the product would exceed the second power of x with is where your expression (1 - 23x - 22x^2) stops
just multiply the terms you found in part a with (1+ax+bx^2)
it's ok
ok so first of all what you will ulimatly do is compare the coefficients of the three first powers of x (0,1,2) with (1-23x-222x^2)
so rewrite youre expression but this time ignore any term with power highr that 2
brilliant, so now we need to express a and b as coefficients of the powers of x to do that we rewrite the result in descending powers of x and get x^2 as a common factor for the 2 powers of x and x as commpn factor for the 1 powers of x.
yes! so know you just compare your coefficients and you find a and b
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what's my mistake
what makes you think you made a mistake
reaching that result just means that'll be true where defined
idk it sounds wrong
oh
i thought i would find x = something
this result basically means that the equation is true for all x
and since those functions are defined in the given interval
the whole interval will be the solution set
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Do you guys think the right side is a correct graph
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how to calculate the limit of this sequence
Look at degrees of num / denom
so we have to convert it into a proper fraction?
You could I suppose
But each of the two terms has larger degree in the num than the denom
this diverges then?
Yes
is this enough evidence that the sequence diverges and the limit doesnt exist?
did I messed something up?
Hmm
I suppose you should actually get a common denom and combine the two fractions into 1 first
interesting
Then factor out n^2 from num and denom
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Can someone help me cros reference?
Should be |c| you have at the end
But that's fine other than that, now you want to consider what that limit becomes to conclude convergence/divergence
u think i should show more work or is that fine
I think that's fine, if anything maybe e.g. divide the numerator and denominator by n^2 to make clearer why that fraction has limit 1, but other than that (and the previously mentioned |c|), it's fine-
As per before, now state what you want |c| to be for convergence, and for divergence-
Sure 
@whole coral
Also missing out absolute value signs for the first one (the second they state you're greater than zero, so I'll let you live oh nvm, the first one they say that too
)
But yeah, they'll converge when the limit is < 1, diverge when the limit is > 1
interesting they do that here as well, c > 0
they really should have made you check both positive and negative values 
yea the questions feel pretty similar
Remember that the ratio test tells you that (for this one) c > 1 means you must diverge and 0 < c < 1 tells you you must converge, but you have to find other ways to check convergence for c = 1
if you set c = 1, what series do you get? Is it a convergent one?
Um idk tbh
im blanking rn
but i'd say no?
what series tests do you know?
root, ratio, integral, limit comparison, alternating and absolute convergence
well, I mean the integral test may help here-
I will save you and tell you that the series $\sum_{n = 1}^{\infty} \frac1{n^2}$ does converge (it in fact converges to $\frac{\pi^2}6$ in fact, but yea)
@whole coral
Using the integral test, you can find the "$p$" series tests (
who names these) which tells you $\sum_{n = 1}^\infty \frac1{n^p}$ converges when $p > 1$ and diverges when $p < 1$
@whole coral
i see wym now ok
this is another one I had
i wanted to know if it was correct to grab the integral of dy/y^3
or should I have just got the anti derivative and had it be y^4/4 instead of -1/2y^2
@whole coral c
You do want the integral of 1/y^3 wrt y, but also you didn't do the left hand side right...
Notice you also have that x by itself too...
wait x where
The very first term is x + ...
oh yea thats my b. I could put x in the right denominator right?
numerator 
so itd be like $-\int \frac{x}{4\sqrt{x^{2+1}}}dx$
Draco
accidentally put the 1 in the wrong place but yea
and it'd be like $-\frac{1}{2y^2}=\int \frac{x}{4\sqrt{x^2+1}}dx$
Draco
Yep basically, and that right integral isn't too bad ⛓️
and then $-\frac{1}{2y^2}=-\frac{1}{4}ln\left|x+\sqrt{x^2+1}\right|+C$
Draco
Well, you don't need a ln for that one 
extra negative by accident
mmm ok ok, but correct so far?
I don't think it is 
For one, you can do that integral by substituting, set, say, u = x^2 + 1 and then you get a nice integral
$-\frac{1}{2y^2}=\frac{1}{4}\sqrt{u}$
Draco
Yep, you get $\frac1{2y^2} = \frac14\sqrt{x^2 + 1} + c$, and now, you just need to find the $c$
@whole coral
(remembering to put the original variable back and all!)
$-\frac{1}{2\cdot \left(2\right)^2}=\frac{1}{4}\sqrt{\left(0\right)^2+1}$
Draco
Draco
$-\frac{1}{8}-\frac{1}{4}=:\frac{3}{8},::C=:\frac{3}{8}$
Draco
@whole coral hows it lookin
nice!
so i got it right?
fye
Thats all I ahve for rn. There are some other problems but I havent done them yet
thank you
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What am I messing or missing when trying to calculate the critical points to then find abs max and min?
Isn’t the derivative of the t term 1
Oooh right I left out the 1
And then I don’t know what you did on the second last step, could you explain
Ignore that last part
This is where I am stuck - I can’t remember what to do to get t= for the critical numbers to see what lay within the interval
You definitely can’t take the ^2/3 away from the t like that
